I had an inactive account with AA, hadn't flown with them in years. I didn't bother paying attention to it, and the miles expired. AA was sending me sale promotions every Tuesday, but didn't notify me of the miles. Didn't bother me, since I wasn't their customer any more.

For discussion purposes, say they have 5 million accounts with less than 25k miles, so not enough to redeem. Those accounts have been inactive for 3, 4, 5 or more years. Do you want them to spend $7 million in printing and mailing costs to notify those people, many of whom have moved, forwarding address expired, or died or changed their names? Sure, it would be nice if they did, but I understand their reasoning.

Or should they send 5 million e-mails to 4 year old e-mail addresses? I'd speculate that maybe 2% of those e-mails would even reach the person and get opened and read, and only a fraction of that 2% would do anything about it.